Method of producing phonograph records



Apr. 24, 1923.

v. H EMERSON METHOD OF PRODUCING PHONOGRAPH RECORDS Filed April 20mvem/to c Wcior/[E 771 mm: @t 1Z3 61mm Patented Apr. 24, 1923.

UNITED STATES PATENT UEFECE.

VICTOR H. EMERSON, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS,TO METAL RECORDING DISC COMPANY, INC., A CORPORATION OF NEW YORK.

METHOD OF PRODUCING PHONOGRAPH RECORDS.

Application filed April 20, 1920. Serial No. 375,242.

To all whom/it may concern:

Be it known that I, VICTOR H. EMERSON, a citizen of the United States,residing at the city, county, and State of New York, have invented newand useful Improvements in Methods of Producing Phonograph Records, ofwhich the following is a specification.

My invention relates to methods for mak ing phonograph records, or, moreparticularly described, to the formation of a record surface upon layersof materials which, while not possessing all the peculiar propertiesrequired for phonographic reproduction, contain other important featuresadaptable to strengthening and otherwise improving the record as awhole.

In my co-pending application Serial No.

37 5 ,243 filed of even date herewith and which has matured into PatentNo. 1,416,342 granted May 16, 1922, I have described a disk recordhaving as a component element a thin plate of metal with a layer ofrecord material upon the surface of the metal; and I have therein alsodisclosed in more or less general terms the method whereby the type ofsound record referred to is built up including a flat, cushioning layeras a component element thereof for the purposes described in saidapplication. a

In the present method, however, I employ.

a process that differs in an important detail from the one theredisclosed, wherein by supplying a thermo-plastic layer between the steeldisks the cushioning feature, being only required during the pressingprocess, is eliminated as a permanent element of the record itself.

Therefore as a preliminary step I first predisk is used, as willpresently be described more in detail. The metal surfaces may bevariously treated to render them suitably receptive for permanentcoatings of the kind referred to, but I find from experimentation thateither of two methods may be successfully employed. A coat of japan orany suitable lacquer may be applied by brush or other convenient meansas a relatively permanent adhesive coat upon the surface of many metalsand alloys, particularly on all grades of steel, with or without bakingthe coating thereon, the employment or omission of the latter stepdepending upon the type of paint used,with a view to making the unionmore permanent. bemade sufliciently irregular and pitted to receive thethermo-plastic materials as applied directly thereto.

Upon the disk of metal thus prepared I place a mass or ball ofthermoplastic record material in a central position, and then place thedisk thus provided upon a like quantity of the record material which inturn rests upon the under matrix plate of a phonograph stamping pressand immediately apply the usual pressing or stamping action, bringinginto contact with the mass of record material the top plate of the presssimilarly prgvided with matrix for pressing sound recor s.

As theoppositely disposed matrix plates approach each other, the severalmasses of thermoplastic material simultaneously spread equally in alldirections toward the periphery of the disk, thereby covering each ofthe surfaces of the metal disk with a veneer of record material into therespectiye faces whereof sound records have been impressed.

The quantity of record material thus applied to the top and bottom ofthe disk of metal is first predetermined so as to provide a uniformcovering of the required thickness from center to circumference uponboth faces of the disk, and if desired enough may be added to extend theflow a slight distance beyond the edges forming a smooth edge or rimwith a continuous unbroken surface, which may bepressed or ground downto any desired diameter.

Or, these surfaces may It is to be noted that in thus applying therecord material in the manner described the central mass during thepressing operation of itself supplies the required elasticity to theaction of the rigid pressing plates as they are fully brought together,for as the respective masses of thermo-plastic material are pushedoutwardly under the pressure and heat required in the process, they bothflow equally and simultaneously in all directions, and in this mannerthe one mass is played against the other, the respective circumferencesas they grow outwardly above and below the metal occupy substantiallythe same opposite positions at all points throughout the pressing diskoperation.

The application of my process has thus far been described with referenceto a single metal disk for each record with a layer of record materialupon its two faces. It will be apparent, however, that two such metaldisks may be employed, in which event it will obviously have a surfacecoat of record material upon one face only of eaclnof the disks.

In uniting the disks in the manner described I find it preferable tosecure the parts together by means of a ball or mass of thermoplasticmaterial applied centrally in the manner above described in connectionwith the record material, and in employing substantially the samequantity of thermoplastic material between the disks as of recordmaterial at their outer surfaces, the

. three masses will spread simultaneously and co-extensively, and inthis manner the relatively rigid and unyielding metal layers will offerno serious or unwieldy resistance to the action of the matrix plates,and thus there is avoided the danger of irreparable injury which wouldotherwise be caused to those delicate prepared surfaces.

Having reference to the drawings illustrative of apparatus preferablyemployed in the practice of my improved method, and certain of theproducts thereof Figure l is an edge view of disks and masses ofmaterial in position to be pressed thereon.

Fig. 2 is a view similar to Fig. 1 with the press as it would appear inprocess of action.

Fig. 8 is a view similar to Figs. 1 and 2 after the press has completelyoperated, the layers of material therein shown greatly exaggerated indiametral section largely exaggerated; and

Fig. 4- is an edge view of the finished records.

Referring to the drawlngs, the numerals 1 and 2 are disks f similar formmade from thin metal stamped from sheet steel preferably having a mass 3of record material centrally resting above the disk 1 and an other mass3 similarlyplaced theidisk 2, the,

last mentioned'mass resting upon the lower matrix 4 of the bed plate ofa press such as is used for stamping out phonograph records.

A third mass of thermo-plastic material is also centrally disposedbetween the two quired degree of heat applied to the several masses'ofthermo-plastic material in the usual way the pressure is applied withthe result as shown in Fig. 2, where the press is represented in theprocess of spreading the masses, and then in Fig. 3 where thethermo-plastic material is shown completely.

spread over the surfaces of themetal d sks and uniting beyond the edges,it being seen that the record material in all of the views is shownlargely exaggerated in thickness merely for the purpose of showing moreclearly the interrelation of the parts.

Fig. 4 represents the finished record produced by my process, but withthe respective layers also here shown somewhat exaggerated, inthickness, but otherwise illustrated in substantially their truerelationship one to the other.

The method of applying the record material as a mass to be spread overthe surface by causing the material to flow outwardly has a doubleadvantage, first, in that it produces structurally a superior recordsurfacethan when first spread over the surfaces of the disk and thenimpressed fiat with the matrix plates and, secondly, that it maybeapplied directly to hard, non-yielding materials, such as the metaldisks of the present process, without injury to the matrix plates. In mypresent process I do not consider this method f applying the recordmaterial in itself broadly new except as used inconnection with metaldisks, and

it is believed the method in that particular form is new and highlyimportant, and is desired to be protected by Letters Patent.

Having described my invention, what I claim is:

l. A method of forming sound records which comprises the followingsteps: preparing a thinmetal disk, toughening the surfaces of the diskand applying a mass of thermo-plastic record material to each of saidsurfaces at substantially the centers thereof, applying heat to rendersaid masses plastic and then pressing the sound record groovesintosaidrecord material by means of matrices as said matrices spread saidrecord material upon the surface of the disk. i

2. A method for forming sound records upon ametall disk, tymeansefcorroding-the" surfaces of the metal and applying centrally thereto amass of thermo-plastic ma terial to each face and pressing the samebetween sound record matrices.

3. A method for forming sound records which consists of preparing disksof metal,

separating the disks by means of a mass of thermo-plastic material,applying a mass of thermo-plastic record material to each of the outerfaces of the disks, applied cen- 10 trally in substantial alignment eachwith the other, and pressing the masses flat upon and between said disksby means of matrices having sound records in the surfaces thereof.

In testimony whereof I have hereunto set my hand.

VICTOR H. EMERSON.

